* boards/fun.xml.in: added maze 3D
* boards/maze.xml.in: added maze 2D force
* gcompris.spec.in: added gnuchess requirement
* po/POTFILES.in: updated
* src/boards/algebra.c: (key_press), (get_operand),
(init_operation): added backspace support
* src/boards/chess.c: (start_board), (chess_create_item),
(item_event), (engine_local_cb), (write_child): now works with gnuchess 5 only
* src/boards/maze.c: Christof Petig <christof@petig-baender.de> implemented a 3D mode
* src/boards/reversecount.c: (process_ok),
(reversecount_create_item): Changed the tux to a top view 4 direction one
* src/gcompris/soundutil.c: (scheduler), (gcompris_play_ogg): removed comments